Entry of Gif/Sticker from Android keyboard

The compiled app from this Github link is shown in the image.
The user is attempting to send either a GIF or a sticker to this chat app from an Android keyboard’s gif/sticker feature, but its says " This pertaining content cannot be entered in". Obviously the sample app doesn’t have the needed code.
The question is how would one right code to accept sticker/gif’s from Android keyboard?